The network according to police was implicated in positive doping test of competitors at the 2008 Beijing Olympics, cycling’s 2010 Tour of Spain and 2009 Tour of Portugal, as well as the 2010 Spanishathletics championships.

The operation began last summer when police were investigating a shop in Mataro, near Barcelona, that sold anabolic steroids to sportspeople, officers said.

The shop was allegedly linked to a Catalan athlete’s positive test for a synthetic steroid called EPO, or erythropoietin, in the 2010 Spanish athletics championships.

The shop received EPO from Morocco via two people, one of whom was a nurse at a dialysis centre, “where he is suspected of stealing different types of EPO.”

Police disclosed that Alberto BN was head of the network and that in seven raids they seized documents, growth hormones and various steroids including a type of EPO known as CERA (continuous erythropoietin receptor activator).